Option Explicit
 
Private Declare Function FindWindow Lib "user32" Alias _
      "FindWindowA" (ByVal lpClassName As String, ByVal _
      lpWindowName As String) As Long
 
Private Declare Function PostMessage Lib "user32" Alias _
      "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, _
      ByVal wParam As Long, ByVal lParam As Long) As Long
 
Const WM_COMMAND = &H111
Const MIN_ALL = 419
Const MIN_ALL_UNDO = 416
 
Private Sub cmdMinAll_Click()
  Dim lHandle As Long
 
  lHandle = FindWindow("Shell_TrayWnd", vbNullString)
  Call PostMessage(lHandle, WM_COMMAND, MIN_ALL, 0&)
End Sub
 
Private Sub cmdMinUndo_Click()
  Dim lHandle As Long
 
  lHandle = FindWindow("Shell_TrayWnd", vbNullString)
  Call PostMessage(lHandle, WM_COMMAND, MIN_ALL_UNDO, 0&)
End Sub